Determinants and incidence of depression in multiple sclerosis: A prospective cohort study

Objective: To estimate the incidence and explore potential determinants of incidence of depression in MS. Methods: A prospective cohort study used a sample of 192 patients from the southern Alberta MS clinic registry. Participants completed baseline risk factor assessment questionnaires using either online, mail or telephone surveys, and completed the Patient Health Questionnaire every 2 weeks for 6 months to assess depressive symptoms in real time. Risk factors assessed included biopsychosocial variables such as socioeconomic status, illness-related factors, childhood risk factors, psychosocial factors, and health behaviors. Cox proportional hazard models were fit to estimate predictors of incidence. Results: 2-week incidence of depression for females was 0.019 (95% CI 0.013-0.029) and for males was 0.044 (0.026-0.074). Strongest predictor of depression incidence risk included fatigue impact, low mobility, resiliency, self-esteem, self-efficacy, and coping style. Conclusion: Depression in MS exhibits a risk factor profile similar to that of depression in the general population, with the additional impact of MS illness-related factors. Potentially modifiable risk factors, such as coping with stress and resiliency, present opportunities for focus of further research in depression in MS treatment and prevention efforts. Some differences in determinants of incidence were found compared to the prevalence risk factors, highlighting the danger of using cross-sectional data to make assumptions about risk. For example, the finding that depression incidence was higher for men is opposite to the higher depression prevalence estimates found for women as well as the consensus in the literature.